Dualmode System Design Odds and Ends


Francis Reynolds

October 3, 2000


The present disturbing news on Firestone tire failures illustrates one of the four reasons why I think using pneumatic tires on the guideways would be a very bad choice. If tire failures were to occur on the guideways the results could be catastrophic.


Kim Goltermann acknowledged relative ignorance of maglev. I suffer from the same deficiency Kim, and I expect most of our fellow dualmode debaters also wish they knew more about maglev and linear motors. There have been many popular articles, patents, and technical papers on maglev, but I haven't found a "Maglev 101" text. Are there any readers out there who can steer us to some basic undergraduate maglev engineering information? We do have the quite technical 1999 text, "Linear Synchronous Motors" by Gieras and Piech, but it doesn't get into magnetic levitation significantly.

Several members of our debate group seem to reject maglev for dualmode systems because of their own relative ignorance of it, or because they suspect that it is too costly, expensive to maintain, inefficient, or because of other unresearched and unproven concerns. To assume that maglev is guilty until proven innocent is a very shortsighted attitude when undertaking the preliminary design of a system that will cost hundreds of billions, will carry a hundred millions or more human beings daily, will need to solve critical energy problems, and need to reduce earth-threatening environmental problems. Aren't those stakes high enough to justify the research to find out which guideway car-support system is the best choice?

In the meantime I will personally direct my influence toward the selection of maglev, not because I know all about it but because of the following facts and arguments: Maglev was invented by rocket-pioneer scientist Robert Goddard, and was featured in the November 1909 issue of Scientific American Magazine. The technology is well developed; the maglev train speed record is 350 mph.

Developmental maglev trains have carried over two and two-thirds million paying passengers without an accident. HSST Maglev train rides were sold to the attendees of the world fairs in Vancouver BC Canada and Yokohama Japan a few years ago (Thanks for the info. Dave) and Transrapid 07 maglev rides are being sold in Germany on the Emsland Test track. Dualmode group member Erik Driessens recently reported to us on personally taking an 80 km (49.7 mile) maglev ride on that track at a top speed of 403 km/h (250.4 mph). Maglev technology is ready for use.

But there are no maglev trains in regular revenue service, and few if any are actually being built at this time. In my opinion this is not due to technological problems nearly as much as it is due to the fact that the basic concept of passenger railroads is obsolete, and they can't solve our current traffic problems. But we cannot logically condemn magnetic levitation per se because it is being used to support dead horses. Maglev and LSM will have tremendous advantages in a national dualmode system. Also, further refinements in maglev technology will be taking place in the years during which a dualmode system is being debated. It would make no sense to me to build an interim nonmaglev system first, and plan to convert it to maglev later.


None of us have designed anywhere nearly a complete system, and no one of us or any small company is going to design the national dualmode system single-handedly. It is going to be designed by a large number of experts in many fields and many companies over a huge number of man-hours. Our small group is unable to know what system design these massive forces will eventually arrive at. It is unlikely that any of us will make the major dualmode decisions for the nation.

But perhaps some of us will be able to influence some of those decisions. And as Van Metre Lund reminded me, occasionally a Microsoft is born. It is possible that one or more of your fledgling dualmode companies will take off and play a major roll in the development of the national system. But only those that support the eventual national system choices will survive. We can have only one type of national guideway system.


You are right Kim, because of the great amount of power and therefore energy required to travel very fast we should never transport routine nonperishable freight on high-speed guideways. The V2 factor in the drag formula is of course the problem. But we will still have the freight railroads and big rigs on the semivacant highways to carry slow freight. We should carry only time-critical freight such as produce, packages, and mail on the guideways. Guideway freight will replace not only many trucks but also much airfreight. Since the remaining big rigs will have the highways mostly to themselves their drivers will be happy. And so will the private car and bus passengers on the guideways be happy, since they will no longer have the driving stress of competing with eighteen wheelers.


Carrying people at high speed also takes a lot of energy—and we have a lot of people. Most people going any distance wish to get there faster and they are willing to pay for that greater speed. The existence of passenger airlines is proof. But the coming energy crisis will be a major factor in determining how much we will have to pay in guideway fees to get the speed we want. With Automated Highway Systems (which use internal-combustion engines) aerodynamic drag and tire-flexure drag would be serious disadvantages in an oil-starved world. But except for the necessary transition period we would never propose a dualmode system using IC on "our" guideways. Getting away from petroleum is one of the major claims of superiority of dualmode over AHS.

How important the drag factor will be will depend in part upon what combination of energy sources we end up using to generate the electricity for the guideways. We have enough coal for several hundred years, but mining is labor intensive and coal is not green. On the 24th of August Dr. Guadagno proposed to us an extensive and intriguing national solar-electric power system. But many questions, such as solar-system cost, maintenance, and solar-cell life remain unanswered. Unfortunately "free" energy is far from free when we include the design, construction, and operation of the systems to harness it. If we are fortunate enough to develop inexpensive and renewable sources of electricity, economical guideway speeds will be higher. We need controlled-fusion power badly—but it must be cheap, safe, and green.


Switching worries you Kim? Don't let it. That is the least of our worries with either pneumatic tires or maglev. The basics of the "guide left-guide right" guidance and switching concept many of us propose were successfully used at least as early as the 1970s (in the single-mode Morgantown, WV University People Mover system). The Morgantown system (which I helped design at Boeing, and have ridden on) is still in full-time driverless operation. It has the "simple, fool-proof, full-speed" switching that Kim wisely requires. But his words, "that can accomplish the switch function in a fraction of a second to facilitate short headway operation" seems to indicate misunderstanding of the concept.

As explained in the /itrans/hilo2.htm "supplementary" article and shown in figures 3 and 4, "fraction of a second" switching is neither necessary nor desirable. A switching signal issued by the navigation computer to the switching mechanism in a vehicle, directing it to follow the desired guide rail, will take place many yards in advance of that vehicle's arrival at a junction. It will work at any speed, but the higher the guideway velocity or the slower the operation of the switching mechanism the earlier the switching signals must be sent to the vehicles. If we use maglev the guidance and switching system in each vehicle or pallet needs only one moving part. If that part fails to move when it is ordered to, or if no order is received, that vehicle may be misdirected, but no accident will occur. The mechanism in the car is a binary toggle, like a light switch. It is in either one way or the other; it won't stop part way.


On August 28 William Turnbull gave us "Some Thoughts on Guided Personal Transit." Welcome to the group, William. You wrote that you feel the scope of a scheme is too broad if "the same system can provide relief for urban problems as well as provide the means for inter-city transit." Most of us dualmode proponents feel just the opposite. I think that the most wonderful virtue of dualmode is that it has many virtues. It can and will do many things much better than they are now being done. "Relief for urban problems and inter-city transit" are only two of the important ones.

Our dualmode system will be a bargain because we will only have to buy one guideway system and in most cases use only enough land for one guideway lane in each direction. Yet almost miraculously that will solve or greatly reduce most of our transportation problems and transportation-related environmental and energy problems. It would be a crime to not take advantage of all of the gains that dualmode offers. I observe painful and ample proof that trying to solve transportation problem one at a time is costly, ineffective, time consuming, wasteful, and frustrating.

From a system standpoint I look upon dualmode as very comparable to our streets and highways system. Depending upon the details of the final design, the guideways may look more like train tracks than they look like roads, but from a system standpoint they will have almost nothing in common with railroads and a great many things in common with streets and highways. Perhaps the most important point of commonality is that the traffic on the guideways will never stop and never change speed. That is the way highway systems should run, and approximately the way they do run until they are overloaded, bad weather, or an accident. As with the highways, all acceleration and deceleration of guideway vehicles must therefore be done in ramps off of the main line. This is all old stuff to most of us, but the point needs to be made to avoid confusing new readers who may not be familiar with the constant-speed guideways and variable-speed ramps concept.

The guideways will be able to do most of the things that streets and highways now do, but do them better, faster, safer, with fewer frustrations, less waste of taxpayer's money, with less depletion of fossil fuels, and less atmospheric pollution including the dreaded world-temperature-raising CO2.

Our interstate highways connect with our city streets; vehicles can freely pass from one to the other. It would have been extremely foolish to make streets that were incompatible with the highways so that the traffic couldn't freely pass their interfaces. It would be equally foolish if we implement separate urban and intercity guideways that are not completely compatible with each other.

The selected guideway speed should probably be different in and around the cities than it is between cities, as several of us have proposed. But the same vehicles must be able to travel nonstop between the low-speed guideways and the high-speed guideways, just as they do between the streets and the highways. As Lund and others of us have implied, there must be a set of standards that will permit all vehicles to travel from sea to shining sea even if the guideways are built and managed by several different companies.


We have written much on the question of whether the cars should be carried on pallets on the guideways, or whether they should be true dualmode cars that don't need pallets. Those who haven't kept up with these debates can read all of the pallet pros and cons in contributions of the last few months. But I am pleased to announce a very promising solution to the "pallet problem." Van Metre Lund, myself, and perhaps others of you now predict that the guideways will carry both true dualmode and palleted vehicles.

My main objection to guideway-system-provided pallets has been that I foresaw they would cause a great increase in guideway system cost and complexity, and cause a significant reduction in system capacity. A recent breakthrough in my own thinking is that pallets can and should be used, in addition to true dualmode cars, but the pallets should not be provided by the guideway system. The guideway company(s) won't buy, store, route, or maintain pallets; nor should any special changes, additions, or provisions be made in the system to accommodate pallets. The system will treat pallets, and their loads if any, the same as it treats true dualmode vehicles.

So where will the pallets come from then? Private enterprise. Pallet rental companies will locate next to the guideways and serve all of those who want to run single-mode vehicles on the guideways. These companies will be something like present car-rental companies, but the rental system will be completely automated so that renting a pallet would be combined with the guideway-entry procedures and require no extra time.

There will be far fewer pallet-rental places than there will be entry and exit ramps for true dualmode vehicles, so single-mode vehicles will have to travel farther on the streets than true dualmode cars will. This will provide an incentive for true dualmode car ownership. The pallet companies will have a lot of business in the early years of the guideways, since few people will have true dualmode cars then. And IC automobiles will still be required for travel on highways where guideways have not yet been built. Pallet rental will decline with time as more people invest in dualmode cars, until most of the pallet rentals will be for hauling boats and other special "trailer" loads on the guideways.

But the pallet rental companies will also rent true dualmode cars, which are expected to become more in demand with time. So the total business of these rental companies may remain reasonably stable. The rental companies will pay guideway fees to shuttle empty pallets and empty rental cars around on the guideways as they need to. Their interface with the guideway system will be like the guideway interface with all other vehicles: through acceleration and deceleration ramps.


It seems to me that most if not all of the ramps connecting to the guideway system should be paid for by the users of those ramps rather than by the system. Conversely, one might argue that if the guideway system invests in a requested ramp, they will eventually earn that investment back from guideway fees collected at that new ramp. But the fallacy there is that the traffic using the new ramp was likely previously driving to a more distant ramp to get on the guideways, and the guideways system did not collect more money as a result of adding the new ramp. Hence the system would usually oppose adding needed ramps. Let city street departments buy as many ramps as they want. The street department might come out ahead by installing more guideway ramps, since getting traffic off the streets sooner will reduce their wear and tear. Much less bureaucratic haggling. And let commercial enterprises also pay for their own ramps. The water company provided service past my house, but I paid for the line into the house as well as pay for the amount of water I use. I also own my own driveway.


I have always assumed that there would never be Personal Rapid Transit, as it is now defined, in our national dualmode system, but Walt Velona included PRT in his vision of the system. We must make available some forms of public and privacy guideway transportation for people without cars and for people who do not drive or don't wish to drive. But what forms of such services make the most sense in a transportation system that includes streets, highways, and extensive national dualmode guideways?

Some local transit buses will be dualmode so riders won't have to walk to the nearest guideway ramp, and/or so that we won't have to build the guideways very close together and provide many ramps. Dualmode transit will require far fewer ramps because in street mode the street bus stops can be as close together as necessary at essentially no additional cost.

As a number of us have noted, driverless buses can be used in guideway-only mode for both local transit and cross-county Greyhound-type services. The cross-country service will be far faster than highway buses for two reasons: The cross-country guideways will be higher velocity than our highways (HiLoMag recommends 200 mph). And the long-distance buses will be smaller and loaded for single destinations so that there will be no time wasted with intermediate stops. The cost of drivers makes small highway buses uneconomical, but guideway buses will require no drivers.

Rental cars will be dualmode, and the rental rates will be lower than present rental cars are because these cars will last much longer on the guideways than highway rental cars do. Dualmode rental car rates will also be lower because there won't be multiple offices full of paid clerks. The "rental agreement" for a dualmode rental car must be made automatically in seconds much as is proposed for "renting" a PRT vehicle. Potential rental customers will be prequalified the same as drivers are licensed and personal credit is preapproved. The cars on a ramp will automatically queue past waiting customers the same as a string of taxis picks up fares at an airport. Long one-way trips by rental car will be more common than they are now. The rental companies will redistribute empty cars as required using the guideways.

Dualmode taxis will be interesting. A taxi driver will be able to pick up a passenger in street mode, deliver the taxi and his/her "fare" to a guideway entry stop, and then get out and let the driverless taxi transport the fare on the guideways. The now temporarily unemployed driver will wait (in a little shelter) for another fare to arrive in another driverless taxi at the adjacent guideway exit stops. Such a system of course requires that dualmode taxis be company owned, not driver owned.

One or more people could take a single taxi all the way from San Diego to Boston, have privacy (and the driver's empty seat to sprawl in) almost all of the way, and pay a driver only a little at each end of the trip. Taxis will also sometimes be redistributed empty and driverless.

Dualmode rental cars and dualmode taxis will fill the personal-privacy transportation market. I see nothing that a single-mode PRT system could contribute that these two services combined won't do better. We could never justify the cost and land requirements of separate dualmode and PRT guideways on the same routes. And if we ran guideway-only (single-mode) PRTs on the dualmode guideways we would have to put in perhaps five times as many entry and exit ramps so the PRT riders wouldn't have to walk far. This would greatly increase the cost and physical size of the system. Dualmode rental cars and dualmode taxis will both provide door to door service, single-mode PRT could not. Dualmode will make the whole concept of PRTs obsolete. I think that single-mode PRT will die in its infancy, along with maglev trains.


Last modified: October 03, 2000